A 26-year-old man has pleaded guilty to charges he robbed six banks in the Waterloo area.The Waterloo-Cedar Falls Courier reports that Jay Harkless made his plea Tuesday in Black Hawk County District Court.A sentencing date has not been set.Authorities say Harkless hid his identity with hoods and wigs when he robbed the banks between November 2008 and May 2009. He was arrested in January 2010.Harkless is serving prison sentences for robberies in Johnson and Muscatine counties.